4.3 Intake and Output (I&O)
Key Takeaways
- All fluids and foods liquid at room temperature count as intake: water, juice, milk, coffee, broth, gelatin, ice cream, sherbet, popsicles
- Ice chips are recorded as half their volume (e.g., 240 mL of ice chips = 120 mL of intake)
- Standard conversions: 1 oz = 30 mL, 4 oz = 120 mL, 6 oz = 180 mL, 8 oz = 240 mL, 1 cup = 240 mL
- Normal adult urine output is ≥30 mL/hour or ≥720 mL/day; report urine <30 mL/hour for 2+ consecutive hours
- Read a graduated container on a flat surface at eye level, at the bottom of the meniscus — never tilted in the air
Intake and output (I&O) is the running 24-hour record of all fluid a resident takes in and puts out. The nurse uses this record to spot dehydration, fluid overload, kidney problems, and bleeding. CNAs measure and record I&O; the nurse interprets it.
All values are recorded in milliliters (mL) — never ounces, cups, or "a lot." Volumes are added at the end of the shift and at midnight to produce a 24-hour total.
What Counts as Intake
Intake includes anything that is liquid at room temperature plus IV fluids the nurse records.
| Counts as Intake | Does NOT Count |
|---|---|
| Water, juice, milk, coffee, tea, soda | Solid foods (bread, meat, cooked vegetables) |
| Broth, soup (liquid portion) | Yogurt, pudding (semi-solid; facility policy varies) |
| Gelatin (Jell-O) | Casseroles |
| Ice cream, sherbet, popsicles | Bananas, apples |
| Tube feedings (recorded per nurse) | — |
| IV fluids (recorded by nurse) | — |
| Ice chips: count as HALF the volume | — |
Ice Chip Rule
Ice chips melt to about half their solid volume. A 240 mL (8 oz) cup of ice chips contains roughly 120 mL of water when melted. This is the most-tested I&O conversion on the NNAAP written exam.
Common Conversions
| Household | Metric (mL) |
|---|---|
| 1 teaspoon (tsp) | 5 |
| 1 tablespoon (tbsp) | 15 |
| 1 ounce (oz) | 30 |
| 1/2 cup (4 oz) | 120 |
| 3/4 cup (6 oz) | 180 |
| 1 cup (8 oz) | 240 |
| 1 pint (16 oz) | 480 |
| 1 quart (32 oz) | 960 |
| 1 liter | 1,000 |
Worked Example
A resident's breakfast tray contains:
- 4 oz orange juice — drank all → 4 × 30 = 120 mL
- 8 oz coffee — drank half → 4 × 30 = 120 mL
- 6 oz milk — drank all → 6 × 30 = 180 mL
- 4 oz cup of ice chips, finished → (4 × 30) ÷ 2 = 60 mL
- 1 cup of Jell-O (4 oz) — finished → 4 × 30 = 120 mL
Total breakfast intake = 600 mL.
What Counts as Output
Output is any fluid leaving the body:
- Urine (the biggest piece — most exam questions are about urine output)
- Emesis (vomit)
- Liquid/diarrheal stool (formed stool is recorded as a bowel movement, not as I&O volume)
- Wound drainage (measured from drains or estimated by saturated dressings per nurse policy)
- Nasogastric (NG) tube drainage / suction
- Blood loss (estimated)
- Insensible losses (sweat, exhaled water) — not measured
Measuring Urine
- Have the resident void into a bedpan, urinal, or collection hat (placed under the toilet seat).
- Wear gloves.
- Pour the urine into a graduated container ("graduate").
- Place the container on a flat surface — not in the air.
- Read the volume at eye level, at the bottom of the meniscus.
- Empty into the toilet, rinse the container, return to the resident's bathroom.
- Record the volume immediately on the I&O sheet.
Catheter bags are emptied at the end of the shift (and earlier if more than half full). Drain into a graduate without touching the spout to the floor or container.
Normal Urine Output and Reportable Thresholds
| Parameter | Normal Adult |
|---|---|
| Hourly urine | ≥30 mL/hour |
| 24-hour total | ≥720 mL (typically 1,200 – 1,500 mL) |
| Color | Pale yellow / straw |
| Clarity | Clear |
| Odor | Mild |
Report to the nurse:
- Urine <30 mL/hour for 2 or more consecutive hours (oliguria)
- No urine output (anuria) for 8 hours
- Dark amber, red/pink, cloudy, foul-smelling, or sediment-filled urine
- Burning, urgency, or sudden incontinence
- Sudden change in output volume up or down
Documentation Tips
- Record immediately after each event — do not save the math for the end of shift.
- Use mL only.
- Total intake and output separately at the end of each shift.
- A positive balance (intake > output) flags fluid retention; a negative balance flags dehydration.
- Most facilities expect a 24-hour balance within about 500 mL of equal for a stable resident; outside that range the nurse re-evaluates.
Special Situations
- NPO (nothing by mouth): record "NPO" in the intake column; oral intake = 0.
- Fluid-restricted residents (e.g., CHF): note the daily limit on the I&O sheet so each shift knows how much remains.
- Force-fluids orders: aim for the volume per shift specified by the nurse; document refusals.
At lunch, a North Carolina nursing facility resident on strict I&O consumes: 8 oz of milk, 4 oz of beef broth, 4 oz of vanilla ice cream, and a 6 oz cup of ice chips. What total intake should the CNA record in milliliters?
A CNA empties an indwelling catheter bag at the end of an 8-hour shift and records 180 mL. The previous shift recorded 220 mL and the shift before that recorded 200 mL. Which action should the CNA take?